Tait TM8100 mobiles Service Manual page 373

Task 21 —
Check Power
Control
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
Check the power-control circuitry if the clamp current for the PA driver is
correct or if the voltage at the
Important
Ensure that the current limit on the DC supply is 2A.
And, when entering the CCTM command 304 z, do not
specify a value z higher than that recorded in
ure to do so might result in the destruction of the PA driver.
Enter the CCTM command 304 z (where z was recorded in
1.
2. Note the current reading on the DC power supply.
Enter the CCTM command 114 0 to switch off the power.
3.
4. Note the current reading on the DC power supply.
5. Compare the above current readings. The current should decrease by
an amount approximately equal to the offset given in
If it does, go to
not, go to Step
6. Check that the voltage from the DAC is changing. Measure the
voltage at the
PWR
Enter the CCTM command 114 1023. The voltage should increase
7.
to:
PWR test point: 2.4 ± 0.1V
Enter the CCTM command 32 to place the radio in receive mode.
8.
9. If the voltage at the
Task 22. If it does not, go to
page 399.
test point is incorrect.
SET PWR
Task 25 in "RF Signal Path" on page
6.
test point (
CDC TX PWR CTL
test point increases as required, go to
PWR
"CODEC and Audio Fault Finding" on
Transmitter Fault Finding (25W)
Task 12. Fail-
Task 12).
Table 12.6.
380. If it does
) (see Figure 12.8).
373